Trench-forming, pipelaying and trench wall supporting machine

ABSTRACT

A generally U-shaped body has a pump mounted near one end to displace a digging plate having a semicircular profile. This produces a trench with a semicircular bottom, shaped to receive and support a pipe section of approximately the same radius as the radius of the curved trench bottom.

Umted States Patent [151 3,638,438 Kinnucan, Jr. Feb. 1, 1972 [54] TRENCH-FORMING, PIPELAYING AND 3,2(l)4,4l5 9/1965 Hill, Jr. et al. ..61 /4l NC W L SUPPORTING 3,2 4,919 11 1965 Kusatake 61/72.l X MACHINE 3,377,806 4/1968 Morrice ..6l/4l 3,381,478 5/l968 Wells ..6l/4l [72] Inventor: Walter F. Kinnucan, Jr., 140 Blackstone,

La Grange, Ill, 60525 Primary Examiner-Jacob Shapiro Alt -J J. J J 22] Filed: Mar. 24, 1970 ames ennmgs r [2l] Appl. No.: 22,334 ABSTRACT A generally U-shaped body has a pump mounted near one end 521 US. Cl ..6l/72.l, 61/41, 61/43 to displace digging Plate having a semicircular profile This [51] Int. Cl ..F16l 1/00, E2ld 11/00 Produces a trench with a semicircular bottom, shaped to [58] Field of Search ..6l/72. 1, 72.5, 72.7, 72.2, receive and Support a P Section of approximately the Sam 61/41, 2 4 33 radius as the radius of the curved trench bottom.

[56] References Cited 6 Claims 3 Drawing Figures UNITED STATES PATENTS 2,738,745 3/1956 Harpold....; ..6l/72.l 1,638,343 8/1927 Knudsen; ..6l/72 .l

PATENIEU rm 1 m 3.638.438

Inventor I WalterF. Kinnucomdr.

Attorney TRENCH-FORMING, PIPELAYING AND TRENCH WALL SUPPORTING MACHINE BACKGROUND OF THE INVENTION In the installation of sewers, pipelines, and other lines comprised of individual pipe sections, it is common practice to dig a trench for receiving the pipe sections. Each pipe section is lowered into the trench and then engaged with the previously laid pipe section. The entire pipeline is then covered over. To dig the trench a unit such as a dragline, backhoe, or other machine is generally used. Such a machine digs a trench the bottom of which is rectangular in cross section. Frequently gravel or other bedding material is then placed as a support base in the trench, and the circular pipe section is then lowered into the trench and displaced longitudinally to engage the previously laid section. Then gravel, sand or other select fill is dropped around the sides of the last pipe section in an attempt to fill the relatively large volume between the lower half of the pipe body and the rectangular profile of the trench. It is difficult to adequately fill and compact this loose material, to provide adequate support for these heavy pipe sections of extended length. For this reason it is not unusual for the sections to settle during use to the point that openings appear between adjacent sections, or a pipe section may even be cracked by the severe stresses imposed when the base material settles and no longer supports the pipe section. Trench wall cave-ins with resulting death, or serious injury, are not uncommon.

It is therefore a principal consideration of the present invention to provide a trench bottom for supporting a pipe section, with the trench bottom shaped to substantially conform with the outer diameter of the pipe section, thus obviating stresses on the pipe section caused by the uneven settlement of bedding or uneven distribution of loads in the rectangular trenches.

Another important consideration is to provide a lesser depth of disturbed trench wall, and to retain trench walls in the event of failure.

SUMMARY OF THE INVENTION A trench-digging machine constructed in accordance with the present invention for removing earth preparatory to laying pipe sections comprises a U-shaped body. This body has a pair of vertical sidewalls, the upper portions of which are detachable, and a substantially semicircular bottom portion extending between these vertical sidewalls. The U-shaped body can be formed from a single piece of sheet steel, or the individual wall portions can be riveted, welded or otherwise affixed to the semicircular bottom portion. In accordance with the teachings of this invention, the radius of the semicircular bottom portion is made substantially equal to the radius of the pipe sections to be laid in the trench.

A pump support mounting is affixed adjacent one end of the bottom portion. A trench-digging member includes a substantially semicircular digging plate of approximately the same radius as that of the pipe sections to be laid. A first piston is affixed to the digging plate and extends from the pump support mounting. On the mounting is a hydraulic pump, and a first pump control element is connected to regulate pump operation, correspondingly regulating displacement of the first piston to displace the digging plate away from the U-shaped body and dig the trench with the desired semicircular bottom wall.

In accordance with another important feature of the invention, a pipe section displacement unit is provided, and comprises a substantially circular push plate affixed to a second piston which extends from the pump support mounting. A second pump control element is connected to regulate pump operation to displace the second piston such that the push plate engages a pipe section and forces it into mating engagement with the previously laid pipe section. When the pipe section is firmly seated, continued pressure exerted by the second piston displaces the U-shaped body into the previously dug portion of the trench, readying the apparatus for the next sequence of operations. This digging machine closely follows a backhoe, dragline or trencher which excavates the trench to a practical distance above the trench bottom.

THE. DRAWING In the several figures of the drawing like reference numerals identify like elements and in the drawing:

FIG. 1 is a cross-sectional view of a pipe section laid according to known techniques in a trench of rectangular bottom cross section;

FIG. 2 is a perspective illustration of a trench-digging apparatus constructed in accordance with the principles of the invention; and

FIG. 3 is a sectional illustration of a pipe section laid in a trench of the configuration produced by the apparatus shown in FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 indicates a section of pipe conduit 10 inserted in a trench 11 according to known techniques. As described previously the rectangular cross section of trench 11 is provided with a backhoe, dragline or other unit, and then some fill material such as gravel 12 is inserted in the bottom of the trench. After the pipe section 10 is laid and seated against the previously laid section, gravel 13, or sand or other select fill, is dropped in around the conduit to maintain the desired pipe position until the trench is closed. Such an arrangement allows the gravel and/or other fill to settle, at least partially, before being restrained by the support edges of trench 11, and thereby damage the mating connections or the conduit itself.

In accordance with the present invention an apparatus such as that depicted in FIG. 2 is provided. This apparatus includes a body portion 15, which has a pair of vertical sidewalls l6 and 17, and a virtually semicircular bottom portion 18 extending beneath the sidewalls. This U-shaped body 15 can be formed of a single piece of sheet steel, for example of it-inch thickness, or the sidewalls l6, 17 can be riveted, bolted, welded or otherwise joined to the semicircular bottom portion 18. It is important to note that the radius of the semicircular bottom portion 18 is made only slightly larger than the radius of the pipe section 10, for reasons which will become apparent later in this explanation. A pair of cross support members 19A, 19B extend between, and are affixed to, upper portions of sidewalls l6, 17. The longitudinal distance between support members 19A, 19B is greater than the length of one pipe section 10, for reasons that will be brought out in the operational description hereinafter.

A pump support mounting 20 is attached, for example by bolts, to the bottom portion 18 near one end of the apparatus as illustrated. A first piston 24 is received in this mounting, and this piston extends in a longitudinal direction, that is, substantially parallel with the longer dimension of body 15. A trench-digging member includes a digging plate 23, shaped substantially like a semicircle and having a radius approximately the same as the radius of the U-shaped portion 18 of the main body 15. First piston 24 is affixed to digging plate 23 by rivets, bolts or other suitable means. Piston 24 may be a hydraulic telescoping piston, to facilitate extension and return of digging plate 23.

A hydraulic pump 25 is shown affixed to the upper portion of pump support mounting 20, and a first control element or handle 26 is connected to regulate pump operation to effect longitudinal displacement of piston 24 away from body 15, to provide a digging action as plate 23 is forced through the soil or other material. Of course, if the trench is to be of considerable depth below the ground level, it may be desirable to first provide a rectangular trench as described previously in connection with FIG. 1 of an appropriate lateral dimension somewhat larger than the pipe, and then lower the entire apparatus of FIG. 2 into the rectangular trench to provide the semicircular trench of the shape shown in FIG. 3.

As illustrated in FIG. 3, operation of the apparatus shown in FIG. 2 and described thus far is effective to produce a trench 27 with a semicircular bottom wall portion conforming with the outer dimensions of pipe section 10. The earth supporting the pipe is tightly compacted, and is not broken up or comprised of loose fill as has been the practice with known devices. Not only the support but also the alignment of the adjacent pipe section is substantially enhanced by the use of the arrangement shown in FIGJZ.

In accordance with another important feature of this invention, pump support mounting 20 also receives a second piston 33. A pipe section displacement unit is provided, including a substantially circular push plate 32 affixed to the second piston 33 which extends from the pump support mounting. Piston 33 may also be a hydraulic telescoping piston. A second pump control element 34 is attached to the pump 25 to regulate operation of the pump in order to displace the second piston 33 and ram 32 toward the rear of body 15, away from pump support mounting 20. Handle 34 is first actuated to retract assembly 32, 33 to the right of cross support 19B. Pipe section is then lowered between supports 19A and 193 to rest in the bottom of body 15. Handle 34 is then actuated to move pipe displacement assembly 32, 33 to the left, to engage pipe section 10 and push it to the left into mating engagement with the previously laid pipe section. Side units 35 act as retainers in case of trench wall failures.

It is important to note that, after section 10 is firmly seated, continued operation of handle 34 and pump 25 can be utilized to displace the entire body to the right into the section of the trench just dug by actuation of the trench-digging assembly 23, 24. Accordingly the entire trench-digging apparatus is moved along and the pipe sections 10 are laid in a properly contoured, firmly supporting trench in a manner not possible with known pipelaying apparatus and techniques.

It is noted, that, although pump support mounting is shown firmly and flatly connected to the bottom portion 18 of body 15, in practice this pump mounting is made adjustable. For example, the rear portion of pump mounting 20 can be pivotally attached to lower portion 18, and an adjustable leg or hydraulically actuated push rod positioned in the forward portion of mounting 20. Thus by actuating the leg or push rod in the front portion, the digging plate 23 can be raised each time ram 24 is withdrawn after a trench-cutting motion. Such an arrangement is readily understood and need not be detailed herein.

Another important advantage attendant upon the variable height adjustment of the pump mounting 20 is that the grade of the trench can be electronically controlled. At the present time this is done with grading and paving equipment. Stakes are driven to establish spaced-apart reference points of correct grade, and a wire or taut line is extended along the tops of the stakes to maintain a running index at a preset distance above the desired grade. Equipment is commercially available which includes an upper sensing portion encircling the reference cable and a lower portion for controlling the paving or grading equipment to produce the correct grade. The same equipment can be readily incorporated with the system of this invention to control the shifting of pump support mounting 20 and thus regulate the displacement of digging plate 23 to insure that the desired grade of the trench is produced.

in addition with this invention the bedding material, such as grave], is not required as a support base, because the tightly compacted dirt which has never been disturbed provides very good support for the pipe sections. The foundation is thus substantially improved as contrasted to prior art arrangements. The danger to operating personnel is also reduced, forthe danger of cave-ins is markedly lowered because the square cross section trench need not extend below the bottom of the pipe section to be laid, but only to the midpoint of the pipe diameter as evident from FIG. 3. The amount of labor expended in the laying of an extended pipeline is reduced with a corresponding increase in productivity and safety of the work crew. Joints between mating pipe sections are very tight as a result of the very precise alignment of adjacent sections and the force applied as the piston 33 is extended rearwardly to mate the adjacent pipe sections and simultaneously push the entire assembly 15 forward into the trench.

While only a particular embodiment of the invention has been described and illustrated, it is apparent that various modifications and alterations may be made therein. it is, therefore, the intention in the appended claims to cover all such modifications and alterations as may fall within the true spirit and scope of the invention.

What is claimed is:

l. A trench-digging apparatus for use in providing a semicircular channel in a rectangular trench preparatory to laying pipe sections in the channel, comprising:

a U-shaped body, having a pair of vertical sidewalls and a substantially semicircular bottom portion extending between the vertical sidewalls, the radius of the semicircular bottom portion being substantially equal to the radius of a pipe section to be laid;

a pump support mounting affixed to said body adjacent one end of the bottom portion;

a first piston extending from said pump support mounting;

a trench-digging member having a digging plate which is substantially semicircular in a plane perpendicular to the line of the trench, afiixed to the end of said first piston to provide for displacement of the digging plate away from and forwardly of the U-shaped body to dig the semicircular channel in the rectangular trench; and

a hydraulic pump affixed to the pump support mounting, and a first pump control element connected to said pump to regulate operation of the pump and thus regulate displacement of the first piston to displace the digging plate.

2, A trench-digging apparatus as claimed in claim 1, and further including a pipe section displacement unit, comprising a second piston extending from the pump support mounting, a substantially circular push plate affixed to the end of said second piston, and a second pump control element connected to said pump to regulate operation of the pump to drive the second piston toward the rear of the U-shaped body and displace a pipe section longitudinally for mating engagement with the previously laid pipe section.

3. A trench-digging apparatus as claimed in claim 1, further comprising first and second support members each extending between and affixed to upper portions of the vertical sidewalls, the longitudinal distance between the support members being greater than the length of one pipe section to facilitate lowering of the pipe section into the bottom of the U- shaped body for displacement by the push plate into engagement with the previously laid section.

4. A trench-digging apparatus as claimed in claim 1, and further comprising detachable sidewall units, which act as retainers in the event of trench wall failure, affixed to the vertical sidewalls of the U-shaped body.

5. The method of excavating a channel with a contour generally semicircular at the bottom of a rectangular trench to receive substantially circular pipe sections in the channel, comprising the steps of:

providing a substantially rectangular trench, with the bottom of the trench approximately at the centerline of the pipe sections to be laid;

providing a U-shaped body having a generally semicircular bottom portion conforming substantially with the diameter of the pipe sections to be laid;

providing a trench-digging member adjacent one end of the U-shaped body, which member includes a digging plate shaped similarly to the bottom of the U-shaped body and of approximately the same radius as the bottom portion of the U-shaped body;

intermittently extending the trench-digging plate beyond the U-shaped body to excavate a channel with a semicircular bottom portion in the bottom of the rectangular trench; and

wardly of the U-shaped body to mate with a previously positioned pipe section, and the reaction force of mating the two pipe sections is utilized to provide the intermittent displacement of the U-shaped body into the just-dug channel portion.

i IIK 

1. A trench-digging apparatus for use in providing a semicircular channel in a rectangular trench preparatory to laying pipe sections in the channel, comprising: a U-shaped body, having a pair of vertical sidewalls and a substantially semicircular bottom portion extending between the vertical sidewalls, the radius of the semicircular bottom portion being substantially equal to the radius of a pipe section to be laid; a pump support mounting affixed to said body adjacent one end of the bottom portion; a first piston extending from said pump support mounting; a trench-digging member having a digging plate which is substantially semicircular in a plane perpendicular to the line of the trench, affixed to the end of said first piston to provide for displacement of the digging plate away from and forwardly of the U-shaped body to dig the semicircular channel in the rectangular trench; and a hydraulic pump affixed to the pump support mounting, and a first pump control element connected to said pump to regulate operation of the pump and thus regulate displacement of the first piston to displace the digging plate.
 2. A trench-digging apparatus as claimed in claim 1, and further including a pipe section displacement unit, comprising a second piston extending from the pump support mounting, a substantially circular push plate affixed to the end of said second piston, and a second pump control element connected to said pump to regulate operation of the pump to drive the second piston toward the rear of the U-shaped body and displace a pipe section longitudinally for mating engagement with the previously laid pipe section.
 3. A trench-digging apparatus as claimed in claim 1, further comprising first and second support members each extending between and affixed to upper portions of the vertical sidewalls, the longitudinal distance between the support members being greater than the length of one pipe section to facilitate lowering of the pipe section into the bottom of the U-shaped body for displacement by the push plate into engagement with the previously laid section.
 4. A trench-digging apparatus as claimed in claim 1, and further comprising detachable sidewalL units, which act as retainers in the event of trench wall failure, affixed to the vertical sidewalls of the U-shaped body.
 5. The method of excavating a channel with a contour generally semicircular at the bottom of a rectangular trench to receive substantially circular pipe sections in the channel, comprising the steps of: providing a substantially rectangular trench, with the bottom of the trench approximately at the centerline of the pipe sections to be laid; providing a U-shaped body having a generally semicircular bottom portion conforming substantially with the diameter of the pipe sections to be laid; providing a trench-digging member adjacent one end of the U-shaped body, which member includes a digging plate shaped similarly to the bottom of the U-shaped body and of approximately the same radius as the bottom portion of the U-shaped body; intermittently extending the trench-digging plate beyond the U-shaped body to excavate a channel with a semicircular bottom portion in the bottom of the rectangular trench; and intermittently displacing the U-shaped body into the just-dug portion of the channel to provide room for laying a pipe section in the already dug channel portion.
 6. The method of excavating a channel in a trench as claimed in claim 5, in which a pipe section is displaced rearwardly of the U-shaped body to mate with a previously positioned pipe section, and the reaction force of mating the two pipe sections is utilized to provide the intermittent displacement of the U-shaped body into the just-dug channel portion. 